This invention relates to hydrogen peroxide destroying compositions, and to methods of using the same, which are useful to decrease the concentration of, or even substantially eliminate, hydrogen peroxide present in a liquid medium. More particularly, the invention relates to such compositions, and methods for using such compositions, useful in destroying residual hydrogen peroxide present in a liquid aqueous medium containing a lens, such as a contact lens, which has been disinfected by the action of hydrogen peroxide.
Contact lenses should be periodically disinfected by the user to prevent infection or other deleterious effects on ocular health which may be associated with contact lens wear. Currently, there are several different conventional systems and methods which enable the user to clean and disinfect their contact lenses between wearing times. These conventional cleaning and disinfection systems can be divided into "hot" and "cold" systems. Hot systems require the use of heat to disinfect the contact lenses, whereas cold systems use chemical disinfectants at ambient temperatures to disinfect the lenses.
Within the realm of cold disinfection systems are hydrogen peroxide disinfection systems. Disinfecting hydrogen peroxide solutions are effective to kill the bacteria and fungi which may contaminate contact lenses. However, residual hydrogen peroxide on a disinfected contact lens may cause irritation, burning or trauma to the eye unless this hydrogen peroxide is destroyed, i.e., decomposed, neutralized, inactivated or chemically reduced. Therefore, the destruction of the residual hydrogen peroxide in the liquid medium containing the disinfected contact lens is needed to enable safe and comfortable wear of the disinfected contact lens. As a further enhancement to comfortable wear of disinfected contact lenses, it would be advantageous to treat the disinfected lens in a high viscosity/lubricity medium before placing the lens in the eye.
Associated with the problem of hydrogen peroxide destruction in contact lens disinfection systems are the problems of easy use and user compliance. To enhance ease of use and user compliance, several efforts have focused on one-step disinfection and hydrogen peroxide destruction. In this regard, various time release tablets containing a core tablet and a totally soluble or insoluble coating have been suggested. In addition, disadvantageous foam formation often occurs as the hydrogen peroxide is being destroyed. This can create liquid spillage and make it less likely for the user to effectively and consistently disinfect his/her lenses.
Schafer et al European Patent Application 86-109,361.5 discloses a hydrogen peroxide neutralizer tablet covered with a water-soluble coating to delay the dissolution of the tablet. This publication discloses the use of various soluble polymers, such as cellulose ethers, which include suitable polyhydric alcohols to control the timed release as a coating for the neutralizer tablet. Kaspar et al U.S. Pat. No. 4,568,517 discloses a one step contact lens disinfecting process which involves hydrogen peroxide and a neutralizer having a hydrogen peroxide neutralizing compound in tablet or particle form and a coating encasing the tablet or particles which acts as a delayed release coating. Among the hydrogen peroxide neutralizing compounds disclosed are peroxidase/catalase enzymes. The coating may be made of organically modified cellulose, such as hydroxypropylmethyl cellulose, ethyl cellulose, cellulose acetate phthalate and hydroxypropyl cellulose. No disclosure is provided as to the specific molecular weights of such polymers or as to how to reduce foam formation.
Park et al U.S. Pat. No. 5,145,644 discloses methods for coating catalase core tablets with cellulose derivatives, such as hydroxypropylmethyl cellulose, using ketone components. Cook et al U.S. Pat. No. 5,362,647 discloses disinfecting contact lenses using hydrogen peroxide with delayed release coated tablets including catalase obtained as the result of the action of Aspergillus niger to cause the destruction of the residual hydrogen peroxide. No specifics regarding the molecular weight of the coatings and/or reducing foam formation during hydrogen peroxide destruction are disclosed.
There continues to be a need for one step contact lens disinfecting systems using a hydrogen peroxide destroying component in which excessive foam formation is reduced or even eliminated and a high viscosity/lubricity medium is used prior to placing the disinfected lens in the eye.